Make more methods return error codes

git_revwalk_next now returns an error code when the iteration is over.
git_repository_index now returns an error code when the index file could
not be opened.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

3 files changed, 14 insertions, 5 deletions

diff --git a/src/git2/common.h b/src/git2/common.h
index aae707cb6..3500a2b14 100644
--- a/src/git2/common.h
+++ b/src/git2/common.h
@@ -151,6 +151,9 @@
 /** The path is invalid */
 #define GIT_EINVALIDPATH (GIT_ERROR - 19)
 
+/** The revision walker is empty; there are no more commits left to iterate */
+#define GIT_EREVWALKOVER (GIT_ERROR - 20)
+
 GIT_BEGIN_DECL
 /** @} */
 GIT_END_DECL
diff --git a/src/git2/repository.h b/src/git2/repository.h
index ecf3db99f..ec74305ae 100644
--- a/src/git2/repository.h
+++ b/src/git2/repository.h
@@ -163,11 +163,14 @@ GIT_EXTERN(git_odb *) git_repository_database(git_repository *repo);
 /**
  * Get the Index file of a Git repository
  *
+ * This is a cheap operation; the index is only opened on the first call,
+ * and subsequent calls only retrieve the previous pointer.
+ *
+ * @param index Pointer where to store the index
  * @param repo a repository object
- * @return a pointer to the Index object; 
- *	NULL if the index cannot be opened
+ * @return 0 on success; error code if the index could not be opened
  */
-GIT_EXTERN(git_index *) git_repository_index(git_repository *rpeo);
+GIT_EXTERN(int) git_repository_index(git_index **index, git_repository *repo);
 
 /**
  * Create a new in-memory repository object with
diff --git a/src/git2/revwalk.h b/src/git2/revwalk.h
index 960039a39..841110499 100644
--- a/src/git2/revwalk.h
+++ b/src/git2/revwalk.h
@@ -99,10 +99,13 @@ GIT_EXTERN(int) git_revwalk_hide(git_revwalk *walk, git_commit *commit);
 
 /**
  * Get the next commit from the revision traversal.
+ *
+ * @param commit Pointer where to store the next commit
  * @param walk the walker to pop the commit from.
- * @return next commit; NULL if there is no more output.
+ * @return GIT_SUCCESS if the next commit was found;
+ *	GIT_EREVWALKOVER if there are no commits left to iterate
  */
-GIT_EXTERN(git_commit *) git_revwalk_next(git_revwalk *walk);
+GIT_EXTERN(int) git_revwalk_next(git_commit **commit, git_revwalk *walk);
 
 /**
  * Change the sorting mode when iterating through the